Manufacturers of complex integrated circuits test each circuit using automatic test equipment. Commercial programmable testers are used for such testing. Such testers are programmable to carry out any test sequence on a device under test (DUT) and evaluate the resulting signals generated by the DUT. These highly flexible testers include a large number of input and output terminals to accommodate virtually any DUT pin count, and the appropriate tester terminals are temporarily connected to the terminals of the DUT during a test using automated positioning equipment. A test sequence typically lasts for a few seconds or less.
For DUTs that have RF inputs or outputs, such as an RF receiver/decoder chip, the tester must include RF generators and RF detectors and use RF cabling to and from the DUT. Such RF generators are very expensive since they must have a wide frequency range to accommodate a wide variety of DUTs. Programmable testers that include the capability for testing RF devices are typically three to five times more expensive than programmable testers that only test using non-RF digital and analog signals. An RF generator in a tester sometimes adds $30,000-$100,000 to the cost of the tester, and the RF cabling to couple the RF signals to the DUT requires costly connectors and a complex design to minimize noise and attenuation.
A manufacturer of integrated circuits must purchase many programmable testers, since each different circuit being fabricated needs a programmed tester and set up. It is desirable to reduce the cost of testing RF DUTs by reducing the cost of the test system.